This arXiv preprint (not yet peer-reviewed) models accretion-induced collapse (AIC) of rapidly rotating, magnetized white dwarfs as they near the Chandrasekhar limit, forming protomagnetars that launch low-entropy relativistic outflows capable of accelerating iron-like nuclei to ultra-high energies. The authors estimate an energy generation rate density of a few 10^43 to 10^45 erg Mpc^-3 yr^-1 under optimistic assumptions about outflow prevalence, using analytic and numerical treatments of magnetic acceleration and photodisintegration losses. Unlike earlier magnetar or gamma-ray burst scenarios, this channel predicts a heavier composition at the highest energies with reduced neutrino yields, offering a testable signature for future AugerPrime and IceCube-Gen2 data. Prior coverage has underemphasized the gravitational-wave and kilonova-like electromagnetic counterparts that could accompany AIC events, a multi-messenger link that could distinguish this mechanism from AGN or tidal disruption sources. Uncertainties remain large due to unknown AIC rates and acceleration efficiency; the work is purely theoretical with no observational sample. Related analyses from the Pierre Auger Collaboration (Phys. Rev. Lett. 2023) on mass composition and a 2022 MNRAS study on magnetar-driven outflows provide supporting context for heavy-nuclei acceleration in compact-object environments.